Comparison of deduced amino acid sequences of
methyltransferases. A, Alignment of coffee
N-methyltransferases. Genes, substrates, and accession
numbers are as follows: CaXMT1, xanthosine, AB048793; CaMXMT1,
7-methylxanthine, AB048794; CaMXMT2, 7-methylxanthine, AB084126; and
CaDXMT1, theobromine, AB084125. The sequences were aligned by ClustalW
(Thompson et al., 1994). Identical residues shared by at
least three proteins are shaded in black, and conserved substitutes
found in at least three proteins are shaded in gray. B, Unrooted
phylogenetic tree of coffee N-methyltransferases with
related proteins. Genes, substrates, species nomenclatures, and
accession numbers are as follows: CaMTL1, unknown, coffee, AB039725;
CaMTL2, unknown, coffee, AB048792; CTS1, 7-methylxanthine, coffee,
AB034700; CTS2, 7-methylxanthine, coffee, AB054841; CCS1, theobromine,
coffee, AB086414; TCS1, theobromine, tea, AB031280; JMT, jasmonic acid
methyltransferase, Arabidopsis, AY008434; SAMT, salicylic acid carboxyl
methyltransferase, Clarkia breweri, AF133053; BAMT, benzoic
acid carboxyl methyltransferase, Antirrhinum majus,
AF198492; PEAMT, phosphoethanolamine N-methyltransferase,
Spinacia oleracea, AF237633; CNMT, coclaurine
N-methyltransferase, Coptis japonica,
AB061863; and PMT1, putrescine N-methyltransferase 1,
Nicotiana tabacum, BAA05867. The sequences were compared
using ClustalW, and the phylogenetic tree was generated by TreeView
1.5.2 (Page, 1996). The branch lengths represent numbers
of substituted residues per site.